The psychology and nursing professions appreciate, value and seek to expand knowledge on a woman's healthy adaptation or subsequent depression following childbirth. This study will investigate the effects of psychosocial and biochemical factors on postpartum depression symptoms (PPDS) in a sample of 200 primiparous women. The major emphasis will be to examine, via multiple regression procedures, the predictive influence of the following psychosocial factors on PPDS, assessed several months after delivery: primary dyadic relationship; stressful events; social supports; and cognitive influences. A longitudinal design will be used in which the effects of (1) single point assessments and (2) changes in these factors across time periods are targeted. These are six assessment times spanning the childbirth process from first trimester to 14 weeks postpartum. Each assessment period will involve the administration of a battery of questionnaires assessing the psychosocial factors, depression symptoms, and depression diagnosis. During the final postpartum check, the subtypes of endogenous versus nonendogenous depression will be assessed using the Schedule for Affective Disorders and Schizophrenia and the Dexamethasone Suppression Test. The discriminatory influence of the four psychosocial factors on these two depression subtypes will be assessed. The second component of the study focuses on the association of autoimmune thyroditis and PPDS. In particular, an analysis of covariance will be used to determine whether there are significant differences in PPDS levels, between those women who manifest autoimmune thyroiditis (significant concentration of microsomal antibodies) and those who do not, after psychosocial effects are taken into account. For the subgroup of women who are diagnosed as having autoimmune thyroiditis, thyroid hormone levels will further determine the existence of thyroid dysfunction. Potential differences in PPDS levels for the two subgroups (thyroid dysfunction versus normal thyroid function) will be analyzed using a t-test. Although the biochemical aspect of the study is to be conducted only on a preliminary level, the overall project represents an integrated model for the study of postpartum depression, combining psychosocial and biological factors.